Definition of prostate-specific antigen

prostate-specific antigen (PROS-tayt-speh-SIH-fik AN-tih-jen): A protein made by the prostate gland and found in the blood. Prostate-specific antigen blood levels may be higher than normal in men who have prostate cancer, benign prostatic hyperplasia (BPH), or infection or inflammation of the prostate gland. Also called PSA.